This noise is driving me crazy! I can't figure it out. The noise doesn't start/stop or get louder/softer with acceleration or deceleration. It also doesn't matter if the car is running or off when driving down the road. The simplest of bumps or vibrations make the noise noticeable. I've looked everywhere for loose things such as manifold heat shields, catalytic converter heat shield, the heat shields that follow the muffler, and so on and so forth. Nothing appears to be loose. Perhaps is a bearing of some kind? I can't really say the noise is coming from the engine compartment so much as it sounds to be coming from directly underneath the truck. Can't be fore sure if it's coming from the front or the back or from side to side. It's loud and it's embarrassing. I've only owned the truck for 3 months now and didn't even notice it until I road around with the windows down a couple weeks ago. Any help, advice, or ideas will be greatly appreciated; besides the obvious take it to a mechanic. Don't have discretionary funds to do that at the moment.

This noise is driving me crazy! I can't figure it out. The noise doesn't start/stop or get louder/softer with acceleration or deceleration. It also doesn't matter if the car is running or off when driving down the road. The simplest of bumps or vibrations make the noise noticeable. I've looked everywhere for loose things such as manifold heat shields, catalytic converter heat shield, the heat shields that follow the muffler, and so on and so forth. Nothing appears to be loose. Perhaps is a bearing of some kind? I can't really say the noise is coming from the engine compartment so much as it sounds to be coming from directly underneath the truck. Can't be fore sure if it's coming from the front or the back or from side to side. It's loud and it's embarrassing. I've only owned the truck for 3 months now and didn't even notice it until I road around with the windows down a couple weeks ago. Any help, advice, or ideas will be greatly appreciated; besides the obvious take it to a mechanic. Don't have discretionary funds to do that at the moment.

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I had the same problem on my 99 Tacoma. Its the catalytic converter! Its a huge clanging noise that is as loud as hell! I was also hoping it was a heat shield but it was inside the cc, I had to get a new one. It solved the problem. One thing you can do is find a screwdriver and wedge it between the top of the cc and the frame rail running across, it will keep the cc from moving around thus the rattle stops. You can probably find an offbrand cc for around 100 bucks good luck.

Okay, so there is a front and a rear Cat. I banged both pretty hard with a hammer, yet no noise from either. How can I tell if it's one or the other? If I were to take them off and shake them, would they even reproduce the noise? How sure can I be that this is the source of the problem?

So today I removed both cats and banged them around. Seems as if something was loose in the front cat. Going to have that replaced and see if that solves the problem. OEM part is super pricey!!! Cats all do the same thing right? Would there be any really bad cons for going with a cat that costs $80? Also, all three bolts that attached the front cat to the exhaust manifold snapped. How much will a shop charge to drill those bolts out?

hey I have the same problem I know i need the rear cat but money it tight and I live in cali so $300 +++ ... my noise sound like there's some thing lose and it come's a goes anything else that it may be or anyone know how Ican get a low cost cat cali ok. dealer wants $1500++ for blot on and after market needs to be weld on... All input is welcome...